1. Field of the Invention
The present invention relates, for example, to a communication system suitable for being applied to an apparatus constituted by a communication terminal apparatus such as a mobile telephone terminal and a wireless key apparatus restricting the operation of the terminal apparatus and to a communication terminal apparatus and a wireless key apparatus constituting the communication system.
2. Description of the Related Art
In recent years, a mobile telephone terminal which is one of communication terminal apparatuses a user always taking along in possession has a trend such that various functions other than wireless telephone functions of primary functions are built-in so as to contain multi functions.
For example, there exists such a terminal in which a camera function carrying out a filming of a still picture and a moving picture, a recording and reproducing function of music data, a viewing and listening function of television broadcast or the like is built-in.
In addition, in recent years, there has been rapidly developing a mobile telephone terminal in which a function as a non-contacting IC card is built-in. This non-contacting IC card is utilized as a boarding ticket of transport facilities, a membership card, an employee ID card, a card for price settlement means at a shop or the like. In this case, an authentication process is carried out by performing wireless communication between adjacent reader and writer, so that it is easy-to-use as compared with a magnetic card or the like. It should be noted in a case when an IC card function unit is mounted in a mobile terminal that the IC card function unit is not always necessarily to have a card type shape.
And now, it is preferable for the mobile telephone terminal having multi functions in this manner to be carried out with a process in order to secure some kind or another security for preventing various functions provided in the terminal from being abused when the terminal is lost. In particular, in case of a terminal installed with an IC card function unit, there is a possibility that personal information stored as the IC card function is read out unjustly or unjust settlement or the like utilizing the IC card function is carried out, so that the necessity for a function for preventing the unjust use thereof is high. There are descriptions, for example, in patent documents 1 and 2 that a wireless card which forms a pair with respect to the mobile telephone terminal is prepared and authentication request is wireless-transmitted periodically from that wireless card such that the functions of mobile telephone terminal is made to be restricted in a case when collation with respect to the authentication request cannot be taken.
More specifically, in a case when the mobile telephone terminal and the wireless card exchange ID (identification information) inherent therein periodically and a favorable communication state is maintained, that is, in a case when the ID exchange is realized, the mobile telephone terminal carries out a normal operation. On the contrary, when it is a state where the ID cannot be exchanged, that is, when the communication state is deteriorated or the communication is cut off, the use of partial function in the mobile telephone terminal is to be limited. In other words, it is possible to execute function limitation after presuming a distance between the mobile telephone terminal and the wireless card by utilizing wireless communication characteristics such that a favorable communication is possible when communication distance between the mobile telephone terminal and the wireless card is short and the communication state becomes deteriorated when the communication distance becomes long.
FIG. 1 shows one example of state transition in a terminal function limitation disclosed in related Japanese Patent Application No. 2004-195059 which was filed by the same applicant. FIG. 1 shows states of “page/page-scan mode”, “normal connection mode” and “low power consumption mode”.
In “page/page-scan”, the wireless card side performs transmission process of a transmission signal and the mobile telephone terminal side performs detection of aforesaid transmission signal such that it is attempted whether or not the connection of the wireless card and the mobile telephone terminal can be realized. It is needless to say that it is also possible that the mobile telephone terminal side performs the transmission process and the wireless card side detects the transmitted signal.
In “normal connection mode”, both apparatuses confirm authenticity of the connected partner and carry out a process for shifting to a low power consumption communication process if there is no problem. A sound telephone call period of a mobile telephone terminal or the like also lies in this state.
In “low power consumption mode”, both apparatuses carry out packet transfer with the connection partner intermittently and confirm whether or not the wireless connection between the wireless card and the mobile telephone terminal is maintained.
Procedures on the occasion when limiting the use of the mobile telephone terminal function by utilizing aforementioned three states will be described.
(1) If packet cannot be received in “normal connection mode” and “low power consumption mode” state for a certain predetermined time period, it is deemed to be a connection abnormality or a connection failure (Abnormal LinkLoss) and the connection of the wireless card with the mobile telephone terminal is cut off.
(2) Further, when this connection abnormality is detected, a lock timer is activated. It is defined that a lock timer is a time period after the connection abnormality is cut off until the function limitation of the mobile telephone terminal is carried out.
(3) Then, after the abnormality is cut off, it is shifted to from “normal connection mode” or “low power consumption mode” to “page/page-scan mode (4)” and the mobile telephone terminal or the wireless card attempts a reconnection (paging).
(4) Here, in a case when the paging is succeeded within lock timer period, the lock timer is reset and it is shifted to “normal connection mode” and an operation is repeated from aforementioned 1).
(5) In a case if the paging is not succeeded within lock timer period, the mobile telephone terminal is function-limited (locked). When this function limitation is applied, it may be constituted such that a warning notice rings from the wireless card (warning mode) when the paging is not succeeded within a certain predetermined time period after the lock timer is activated and further the function limitation of the mobile telephone terminal is carried out after the time period elapses.
(6) Here, if a function limitation is applied to the mobile telephone terminal once, the function limitation of the mobile telephone terminal will not be released so long as a reconnection is succeeded by the paging (in this case, it is shifted to a normal connection mode from the paging).
According to abovementioned method, for example, if a user carries a wireless card attached his body and goes away from a mobile telephone terminal by putting only the mobile telephone terminal somewhere as it is, the communication state is deteriorated according to the free space loss or the like, the detection of a packet which a partner device transmits becomes difficult, finally a connection abnormality cut off occurs and a function limitation is executed on the mobile telephone terminal. In this manner, it is possible to execute a function limitation on the mobile telephone terminal when the wireless card is far from the mobile telephone terminal by a constant distance. Further, in a case when a connection can be carried out again after the function limitation is executed, it is possible to release the function limitation automatically. In this manner, it is possible to operate the security function of the mobile telephone terminal without consciousness of a user.
[Patent Document 1] Jap. laid-open patent publication No. 2001-352579
[Patent Document 2] Jap. laid-open patent publication No. 2001-358827